This invention relates generally to an animated display device and, more particularly, to an illuminated display device having a movable film giving the illusion of motion or providing for shifting scenes. "Animated display" is used herein generally to cover both an illusion of motion and a shifting scene.
Animated display devices are well-known in the art. Such devices usually include a shutter film or grid sheet having alternate opaque and transparent strips, an overlying translucent program film having an image thereon, and an illuminating means for generating light which passes through the transparent sections of the shutter film and the program film so as to project a visible image. The program film has a series of strip images so that when the film is moved relative to the shutter film, one of the images is visible during a discrete time interval.
In the prior art, it has been a common practice to utilize a relatively thin flexible sheet for the shutter film and a similar sheet for the program film, since the use of photographic films can expedite manufacture and since the use of movable, rigid, platelike sheets can create special mounting problems.
To avoid parallax, it is necessary that the sheets be held firmly together. A rather costly and intricate method for maintaining the thin sheets together is to mount them between two rigid transparent plates. Magnetic strips have been proposed. In another device, sheets were to be maintained in contact by freely supporting them in facing relationship with the edges of the forward sheet being urged rearwardly and the edges of the rearward sheet being urged forwardly. This practice maintains the edges of the sheets in contact; however, maintaining the center portions of the sheets in contact remains a problem, particularly where differential shrinking of the sheets is encountered.